Traditional retroreflective sheeting materials, such as those disclosed in U.S. Pat. Nos. 3,689,346, 3,712,706, and 3,810,804, the teachings of which are incorporated herein by reference, are described as cube-corner structures that are molded from tooling that comprises of a plurality of element forming cavities (odd generation tooling) which produce cube-corner segments having substantially planar front major surfaces.
Traditional cube-corner prisms have a base with three surfaces intercepting at an apex. As shown in FIG. 1, the prisms are oriented such that the light ray R enters through the base 10 and is retroreflected by the three surfaces 12. This requires that the prisms be formed from a material which allows a significant amount of the light rays to pass therethrough. Thus, the prism material is limited to materials which have this property. Unfortunately, it has been found that these materials are often susceptible to ultraviolet (UV) light, visible light, and/or thermal degradation, resulting in diminished performance capabilities.